1. Field of the Invention
An aspect of the present invention relates to a printer and a duplex printing mode controlling method thereof, and, more particularly, to a printer that shortens printing time by temporarily canceling a duplex printing mode, which is an operational mode to perform printing on both sides of paper, when an amount of print data requiring one side of one piece of paper is inputted into a printer that is preset in the duplex printing mode, and a duplex printing mode controlling method thereof.
2. Description of the Related Art
Although conventional printers output paper with data printed on one side only, advancing printer technology and user's demands call for development of printers capable of performing printing on both sides, i.e., duplex printing. FIG. 1 is a cross-sectional view showing a conventional laser beam printer having a duplex printing capability. As shown in the drawing, the main body 10 of the laser beam printer having a duplex printing function includes a printing path 9 to print an image on paper, an ejecting path 16 to eject printed paper, and a reversing path 20 to reverse the printed paper for duplex printing.
Herein, a pickup roller 12, a feeding roller 13, and a printing unit 14, 15, 18 and 19 are disposed at the printing path 9. The pickup roller 12 picks up paper in a paper supplying cassette 11, and the feeding roller 13 feeds the paper picked up by the pickup roller 12 into the printing unit 14, 15, 18 and 19. The printing unit 14, 15, 18 and 19 is formed of different constitutional elements according to the kind of a printer. Where a laser beam printer is used, the printing unit is formed of a laser scanner 14, a developer 18, a photosensitive drum 19, and a fixing roller 15.
An ejection roller 17 to eject paper from the apparatus is disposed on the ejecting path 16 at an end thereof. The ejection roller 17 also reverses the driving direction under the control of a controller (not shown) to have the ability to transfer the paper in an ejection direction or toward the beginning of the reversing path 20.
Several pairs of transfer rollers 22 to guide paper to the feeding roller 13 are disposed on the reversing path 20.
The operation of a printer having the above-described structure and the duplex printing capability will now be described. When a duplex printing mode is set up and print data is inputted into the printer by a user terminal, rollers as well as the printing unit 14, 15, 18 and 19 are operated. A sheet of paper is picked up by the pickup roller 12 and then transferred to the printing unit 14, 15, 18 and 19 by the feeding roller 13. An image is developed on one side of the paper by the developer 18 and the photosensitive drum 19 of the printing unit 14, 15, 18 and 19, and the image is fixed on the paper by the fixing roller 15. Then, when the paper is ejected by the ejection roller 17, except for one end part of the paper which remains inside the apparatus, the rotation direction of the ejection roller 17 is reversed and the paper is inputted into the reversing path 20. The paper, inputted to the reversing path 20, is then supplied to the feeding roller 13 by the transfer roller 22. There, the paper is supplied to the printing unit 14, 15, 18 and 19 again and an image is developed and fixed on the other side of the paper, which is then ejected from the apparatus by the ejection roller 17.
When the duplex printing mode is set up and an amount of print data requiring one side of one piece of paper is to be outputted, only one side of each piece of paper needs to be printed on. However, the conventional printers perform single-sided printing in the same manner as duplex printing, i.e., ejecting part of the paper, inputting the partially ejected paper into the reversing path 20, and printing print data on the second side of the paper. Therefore, where single-sided printing is required, the printing operation takes an excessive amount of time. This is because, although printing may be carried out through the printing path 9 and the ejection path 16, the paper is inputted again into the reversing path 20 and passes through the printing path 9 and the ejection path 16 unnecessarily. Moreover, since the transfer roller 22, the feeding roller 13, the fixing roller 15 and the ejection roller 17 should be operated while the paper is inputted into the printer again through the reversing path 20 and passes through the printing path 9 and the ejecting path 16, power consumption is increased and the life span of the printer is shortened. These problems also occur when the last side of a last page of print materials having an odd total number of side of pages is printed.
To prevent the above and/or other problems from occurring, when single-sided printing is required, a print option setup window may be activated or the print mode may be switched into a normal printing mode by manipulating menu buttons in the main body of the printer. However, since a user has to go through several selection processes to activate the print option setup window or find a corresponding print setup menu by manipulating menu buttons in the main body of the printer, such solutions are quite troublesome.
Therefore, a method that improves a printing speed by temporarily canceling the duplex printing mode and performing printing in the normal printing mode when the duplex printing mode is set up and a single-sided printing operation or the last page of print materials whose total number of side of pages is an odd number is printed should be sought.